Materials made from natural rubber, latex, or synthetic rubber possess ideal physical properties for various applications, including mechanical strength, low heat resistance, flexibility, and elasticity. Due to these advantages, natural rubber is commonly used in many commercially available products. Natural rubber is cultivated from Hevea brasiliensis, known as rubber trees, and is chemically composed of polymers with repeating units of isoprene (cis 1,4-polyisoprene). Its chemical composition and presence of unsaturated carbon-carbon double bonds contributes to natural rubber's hydrophobic nature, which can result in irreversible adsorption of biological components onto its surface. This limits the possibility of using natural rubber for in vivo applications and devices since latex is non-compatible with blood and can lead to bacterial, fungal, or protein accumulation on the surface.
Methods to modify the physical or chemical nature of natural rubber to possess hydrophilic properties are beneficial to expand the current application of latex to new materials, such as for in vivo devices. For example, guide wires and catheters coated with covalently-linked hydrophilic polymer coatings are used in interventional radiology and cardiology to reduce friction and abrasive forces between the body cavity and device interface. The application of a hydrophilic coating is advantageous for these types of medical devices because of the ability to reduce friction in conduits of the body, such as vascular, biliary, genitourinary and gastrointestinal systems, and to easily move within and traverse complex and tortuous anatomical terrains in viscous solutions, such as blood and bile. Decreasing friction and abrasive forces have resulted in lower complication rates from decreased microtrauma within the host environments and lower rates of infection by limiting aggregation of biological material on the catheter surface.